Normal-state properties of high-temperature superconductors

The doping and the temperature dependence of various normal-state properties of high-temperature superconductors are studied by applying the t-t’-J model. The slave-boson method is used to treat the strong correlations. The fermion quasiparticles carry both charge and spin and the volume of the Fermi surface satisfies the Luttinger theorem. The quasiparticle energy spectrum used in the calculation is obtained from a mean-field treatment of the t-t’-J model. The study is confined to the metallic phase where contributions from the t and t’ terms are most dominant. The calculations provide a quantitative understanding for the doping dependence of Drude plasma frequency, Hall resistivity ${\mathit{R}}_{\mathit{H}}$, band Pauli magnetic susceptibility ${\mathrm{\chi }}_{\mathit{S}\mathit{B}}$, thermopower, and the room-temperature dc conductivity. The temperature dependence of ${\mathit{R}}_{\mathit{H}}$ and ${\mathrm{\chi }}_{\mathit{S}\mathit{B}}$ for small doping are not understood. The calculated density of states, Fermi energy, effective mass, and the Sommerfeld parameter have reasonable values. We have taken J=0 and t=0.45 eV and have considered a wide range of t’ values.